000 AXPZ20 KNHC 080948 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SUN AUG 08 2010 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0900 UTC. ...SPECIAL FEATURE... AT 08/0900 UTC...THE CENTER OF TROPICAL STORM ESTELLE WAS LOCATED NEAR 17.8N 110.3W MOVING TOWARD THE WEST-NORTHWEST OR 290 DEGREES AT 9 KT...AND THIS GENERAL MOTION...WITH A CONTINUED GRADUAL DECREASE IN FORWARD SPEED...IS EXPECTED DURING THE NEXT 48 HOURS. ESTIMATED MINIMUM CENTRAL PRESSURE IS 994 MB. MAXIMUM SUSTAINED WINDS ARE 55 KT WITH GUSTS TO 65 KT. A GRADUAL WEAKENING TREND IS EXPECTED OVER THE NEXT FEW DAYS DUE TO A COMBINATION OF INCREASED VERTICAL WIND SHEAR AND COOLER SEA SURFACE TEMPERATURES TO THE NORTH AND WEST OF ESTELLE. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/ WTPZ22 KNHC FOR MORE DETAILS. ...ITCZ... THE ITCZ AXIS IS ALONG 11N86W TO 12N92W TO 16N106W TO 14N110W TO 11N135W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS WITHIN 240 NM S OF AXIS E OF 90W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 09N TO 16N BETWEEN 91W AND 101W AND FROM 10N TO 14N BETWEEN 106W AND 118W. ...DISCUSSION... AN UPPER LEVEL ANTICYCLONE CONTROLLING THE NW WATERS IS POSITIONED NEAR 24N132W WITH AN UPPER RIDGE EXTENDING BEYOND 32N136W. A SECOND UPPER LEVEL ANTICYCLONIC CIRCULATION IS LOCATED OVER CENTRAL MEXICO NEAR 20N103W WITH A RIDGE AXIS EXTENDING W INTO THE E PACIFIC NEAR 23N120W. TROPICAL STORM ESTELLE IS EMBEDDED IN THE UPPER LEVEL SOUTHEASTERLY FLOW TO THE SW OF THIS ANTICYCLONE. A WEAK UPPER LEVEL TROUGH AXIS EXTENDS FROM NORTHERN BAJA CALIFORNIA ACROSS THE GULF OF CALIFORNIA TO NW MEXICO NEAR 24N106W. AN UPPER LEVEL TROUGH ENTERS THE FORECAST AREA NEAR 32N121W AND CONTINUES S-SW TO 21N123W. VERY DRY AIR ALOFT WITH MODERATE TO STRONG SUBSIDENCE IS PRESENT ACROSS THE REGION N OF 15N AND W OF 116W. ZONAL/EASTERLY FLOW PREVAILS ACROSS THE REMAINDER OF THE DISCUSSION AREA IN THE DEEP TROPICS S OF 12N. UPPER LEVEL MOISTURE RESULTING FROM ITCZ CONVECTION IS BEING ADVECTED TO THE WEST AS A RESULT OF THE PERSISTENT EASTERLY WINDS. UPPER LEVEL DIFFLUENCE IS HELPING TO INDUCE CONVECTION ALONG THE ITCZ IN THE AREAS DESCRIBED ABOVE. AT THE SURFACE...A RIDGE DOMINATES THE NORTHERN WATERS ORIGINATING FROM 1028 MB HIGH PRES CENTERED NW OF THE AREA NEAR 36N143W ENTERING THE DISCUSSION AREA AT 32N135W THROUGH 22N123W. NOAA CORPS SHIP 'MCARTHUR II' NEAR 29N132W HAS BEEN REPORTING 15-20 KT WINDS DURING THE PAST FEW HOURS AND THE FORECAST KEEPS AN AREA OF 15-20 KT WINDS N OF 28N BETWEEN 124W AND 132W DUE TO A TIGHT PRESSURE GRADIENT BETWEEN THE RIDGE AND LOWER PRESSURE OVER SOUTHERN CALIFORNIA. GLOBAL MODELS TRANSLATE THIS AREA TO THE SW OVER THE NEXT 24-36 HOURS AND GRADUALLY DIMINISHES THE WIND FIELD BELOW 20 KT AS A BROAD AREA OF MODERATE TRADES LOCATES W OF 134W. A TROUGH IN THE GULF OF CALIFORNIA IS ALSO RESULTING IN SE TO S WINDS TO 20 KT N OF 29N ALTHOUGH EXPECT THESE WINDS TO DIMINISH BY LATE SUNDAY AS THE TROUGH WEAKENS. ELSEWHERE FARTHER WEST...A WEAK SURFACE TROUGH EMBEDDED WITHIN THE ITCZ EXTENDS FROM 13N136W TO 08N139W. THE TROUGH IS FORECAST TO DRIFT WESTWARD AT AROUND 5-10 KT OVER THE NEXT FEW DAYS. DISTURBANCES ALONG THE ITCZ CONTINUE TO PRODUCE AN AREA OF S TO SW WINDS OF 20-25 KT S OF THE ITCZ TO 06N BETWEEN 90W AND 125W AS CAPTURED BY A PAIR OF ASCENDING ASCAT PASSES AT 08/0352 UTC AND 08/0536 UTC RESPECTIVELY. COMBINED SEAS ARE 8 TO 12 FT FROM LONG PERIOD SW SWELL AND FRESHLY GENERATED WIND SEAS. THIS OVERALL WEATHER PATTERN WILL PERSIST DURING THE NEXT FEW DAYS. CROSS EQUATORIAL SW SWELLS WITH PERIODS OF 13-15 SECONDS DOMINATE THE MAJORITY OF THE FORECAST WATERS. THESE SWELLS WILL GRADUALLY DECAY THROUGH EARLY TUESDAY AS A NEW SWELL TRAIN CROSSES THE EQUATOR BETWEEN 100W AND 135W. $$ HUFFMAN